Photodissociation of Molecular Oxygen (O2)
This movie shows how ultraviolet "light" can break apart a molecule. You need the latest version of the Flash player to see this movie.
Photons are little bits of light. Photons carry energy.
When a photon hits an oxygen molecule, it adds energy to the molecule. The molecule has chemical bonds (they work a bit like stretchy rubber bands!) holding its atoms together. Sometimes the energy from the photon breaks the bond between the two oxygen atoms. The atoms fly apart! This is called photodissociation.
Photons of ultraviolet (UV) light carry more energy than photons of visible light carry. It takes high-energy UV photons to break oxygen apart!
Photodissociation of Molecular Nitrogen
Photodissociation of Water
Photodissociation of the Hydroxyl Radical
Shop Windows to the Universe Science Store!
Our online store
on science education, classroom activities in The Earth Scientist
specimens, and educational games
You might also be interested in:
Text for this level has not been written yet. Please see the "Intermediate" text for this page if you want to learn about this topic. To get to the "Intermediate" text, click on the blue "Intermediate"...more
Oxygen (O2) is a kind of gas. A lot of the air you breathe is oxygen. That's a good thing, since we need oxygen to stay alive! About 4/5ths of the air in Earth's atmosphere is nitrogen (N2). Almost all...more
Most things around us are made of groups of atoms connected together into packages called molecules. Molecules are made from atoms of one or more elements. Some molecules are made of only one type of...more
Photons are little bits of light. Photons carry energy. When a photon hits a molecule, it adds energy to the molecule. The molecule has chemical bonds (they work a bit like stretchy rubber bands!) holding...more
Nitric acid is a very strong kind of acid. If you got some on your skin, it would burn you! Nitric acid has nitrogen, oxygen, and hydrogen atoms in it. Earth's atmosphere has a very, very tiny bit of nitric...more
Sulfuric acid is a very common type of acid. Acid rain has sulfuric acid in it. Acid rain harms plants, fish, and other living things. A type of air pollution causes acid rain. When people burn fossil...more
Methane is a kind of gas. There is a small amount of methane in the air you breathe. A methane molecule has carbon and hydrogen atoms in it. Methane is a greenhouse gas. That means it helps make Earth...more